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Taggart PL, Liddicoat C, Tong WH, Breed MF, Weinstein P, Wheeler D, Vyas A. Gut microbiota composition does not associate with Toxoplasma infection in rats. Mol Ecol 2022; 31:3963-3970. [PMID: 35621391 PMCID: PMC9546062 DOI: 10.1111/mec.16552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/01/2022] [Accepted: 05/25/2022] [Indexed: 11/30/2022]
Abstract
Toxoplasma infection in intermediate host species closely associates with inflammation. This association has led to suggestions that the behavioural changes associated with infection may be indirectly driven by the resulting sustained inflammation rather than a direct behavioural manipulation by the parasite. If this is correct, sustained inflammation in chronically infected rodents should present as widespread differences in the gastrointestinal microbiota due to the dependency between the composition of these microbiota and sustained inflammation. We conducted a randomized controlled experiment in rats that were assigned to a Toxoplasma‐treatment, placebo‐treatment or negative control group. We euthanised rats during the chronic phase of infection, collected their caecal stool samples and sequenced the V3‐V4 region of the 16S rRNA gene to characterize the bacterial community in these samples. Toxoplasma infection did not induce widespread differences in the bacterial community composition of the gastrointestinal tract of rats. Rather, we found sex differences in the bacterial community composition of rats. We conclude that it is unlikely that sustained inflammation is the mechanism driving the highly specific behavioural changes observed in Toxoplasma‐positive rats.
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Affiliation(s)
- Patrick L Taggart
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia, 5371, Australia.,Vertebrate Pest Research Unit, Department of Primary Industries NSW, Queanbeyan, NSW, Australia, 2620.,School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia, 2033
| | - Craig Liddicoat
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia.,School of Public Health, The University of Adelaide, SA, 5005, Australia
| | - Wen Han Tong
- Chief Scientist Unit, Department of Primary Industries NSW, Orange, NSW, 2800, Australia
| | - Martin F Breed
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Philip Weinstein
- School of Public Health, The University of Adelaide, SA, 5005, Australia
| | - David Wheeler
- Chief Scientist Unit, Department of Primary Industries NSW, Orange, NSW, 2800, Australia
| | - Ajai Vyas
- School of Biological Sciences, Nanyang Technological University (SBS-NTU), 60 Nanyang Drive, Singapore, 637551, Singapore
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Yin K, Xu C, Zhao G, Xie H. Epigenetic Manipulation of Psychiatric Behavioral Disorders Induced by Toxoplasma gondii. Front Cell Infect Microbiol 2022; 12:803502. [PMID: 35237531 PMCID: PMC8882818 DOI: 10.3389/fcimb.2022.803502] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 01/17/2022] [Indexed: 11/21/2022] Open
Abstract
Toxoplasma gondii is known to have a complex life cycle and infect almost all kinds of warm-blooded animals around the world. The brain of the host could be persistently infected by cerebral cysts, and a variety of psychiatric disorders such as schizophrenia and suicide have been reported to be related with latent toxoplasmosis. The infected animals showed fear reduction and a tendency to be preyed upon. However, the mechanism of this “parasites manipulation” effects have not been elucidated. Here, we reviewed the recent infection prevalence of toxoplasmosis and the evidence of mental and behavioral disorders induced by T. gondii and discussed the related physiological basis including dopamine dysregulation and gamma-aminobutyric acid (GABA) pathway and the controversial opinion of the necessity for cerebral cysts existence. Based on the recent advances, we speculated that the neuroendocrine programs and neurotransmitter imbalance may play a key role in this process. Simultaneously, studies in the evaluation of the expression pattern of related genes, long noncoding RNAs (lncRNAs), and mRNAs of the host provides a new point for understanding the mechanism of neurotransmitter dysfunction induced by parasite manipulation. Therefore, we summarized the animal models, T. gondii strains, and behavioral tests used in the related epigenetic studies and the responsible epigenetic processes; pinpointed opportunities and challenges in future research including the causality evidence of human psychiatric disorders, the statistical analysis for rodent-infected host to be more vulnerable preyed upon; and identified responsible genes and drug targets through epigenetics.
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Tong WH, Pavey C, O'Handley R, Vyas A. Behavioral biology of Toxoplasma gondii infection. Parasit Vectors 2021; 14:77. [PMID: 33494777 PMCID: PMC7831251 DOI: 10.1186/s13071-020-04528-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/07/2020] [Indexed: 12/14/2022] Open
Abstract
Toxoplasma gondii is a protozoan parasite with a complex life cycle and a cosmopolitan host range. The asexual part of its life cycle can be perpetually sustained in a variety of intermediate hosts through a combination of carnivory and vertical transmission. However, T. gondii produces gametes only in felids after the predation of infected intermediate hosts. The parasite changes the behavior of its intermediate hosts by reducing their innate fear to cat odors and thereby plausibly increasing the probability that the definitive host will devour the infected host. Here, we provide a short description of such parasitic behavioral manipulation in laboratory rodents infected with T. gondii, along with a bird's eye view of underpinning biological changes in the host. We also summarize critical gaps and opportunities for future research in this exciting research area with broad implications in the transdisciplinary study of host-parasite relationships.
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Affiliation(s)
- Wen Han Tong
- School of Biological Sciences, Nanyang Technological University (SBS-NTU), 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Chris Pavey
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Land and Water, Darwin, Australia
| | - Ryan O'Handley
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Roseworthy, Australia
| | - Ajai Vyas
- School of Biological Sciences, Nanyang Technological University (SBS-NTU), 60 Nanyang Drive, Singapore, 637551, Singapore.
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Behavioral Manipulation by Toxoplasma gondii: Does Brain Residence Matter? Trends Parasitol 2021; 37:381-390. [PMID: 33461902 DOI: 10.1016/j.pt.2020.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 12/04/2020] [Accepted: 12/27/2020] [Indexed: 11/22/2022]
Abstract
The protozoan parasite Toxoplasma gondii infects a wide range of intermediate hosts. The parasite produces brain cysts during the latent phase of its infection, in parallel to causing a loss of innate aversion in the rat host towards cat odors. Host behavioral change presumably reflects a parasitic manipulation to increase predation by definitive felid hosts, although evidence for increased predation is not yet available. In this opinion piece, we propose a neuroendocrine loop to explain the role of gonadal steroids in the parasitized hosts in mediating the behavioral manipulation. We argue that the presence of tissue cysts within the host brain is merely incidental to the behavioral change, without a necessary or sufficient role.
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Wang ZT, Verma SK, Dubey JP, Sibley LD. The aromatic amino acid hydroxylase genes AAH1 and AAH2 in Toxoplasma gondii contribute to transmission in the cat. PLoS Pathog 2017; 13:e1006272. [PMID: 28288194 PMCID: PMC5363998 DOI: 10.1371/journal.ppat.1006272] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/23/2017] [Accepted: 03/06/2017] [Indexed: 01/08/2023] Open
Abstract
The Toxoplasma gondii genome contains two aromatic amino acid hydroxylase genes, AAH1 and AAH2 encode proteins that produce L-DOPA, which can serve as a precursor of catecholamine neurotransmitters. It has been suggested that this pathway elevates host dopamine levels thus making infected rodents less fearful of their definitive Felidae hosts. However, L-DOPA is also a structural precursor of melanins, secondary quinones, and dityrosine protein crosslinks, which are produced by many species. For example, dityrosine crosslinks are abundant in the oocyst walls of Eimeria and T. gondii, although their structural role has not been demonstrated, Here, we investigated the biology of AAH knockout parasites in the sexual reproductive cycle within cats. We found that ablation of the AAH genes resulted in reduced infection in the cat, lower oocyst yields, and decreased rates of sporulation. Our findings suggest that the AAH genes play a predominant role during infection in the gut of the definitive feline host.
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Affiliation(s)
- Zi T. Wang
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Shiv K. Verma
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Beltsville, Maryland, United States of America
| | - Jitender P. Dubey
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Beltsville, Maryland, United States of America
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
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Vom Steeg LG, Klein SL. Sex Steroids Mediate Bidirectional Interactions Between Hosts and Microbes. Horm Behav 2017; 88:45-51. [PMID: 27816626 PMCID: PMC6530912 DOI: 10.1016/j.yhbeh.2016.10.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/27/2016] [Accepted: 10/28/2016] [Indexed: 02/07/2023]
Abstract
The outcome of microbial infections in mammals, including humans, is affected by the age, sex, and reproductive status of the host suggesting a role for sex steroid hormones. Testosterone, estradiol, and progesterone, signaling through their respective steroid receptors, affect the functioning of immune cells to cause differential susceptibility to parasitic, bacterial, and viral infections. Microbes, including fungi, bacteria, parasites, and viruses, can also use sex steroid hormones and manipulate sex steroid receptor signaling mechanisms to increase their own survival and replication rate. The multifaceted use of sex steroid hormones by both microbes and hosts during infection forms the basis of this review. In the arms race between microbes and hosts, both hosts and microbes have evolved to utilize sex steroid hormone signaling mechanisms for survival.
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Affiliation(s)
- Landon G Vom Steeg
- W. Harry Feinstone Department of Molecular Microbiology & Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Sabra L Klein
- W. Harry Feinstone Department of Molecular Microbiology & Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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8
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Female house mice initially shun infected males, but do not avoid mating with them. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-1884-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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